The present invention is directed to a method and to a mobile radio telephone network for handling a packet data service.
As known, it is possible to have the connections controlled by an intelligent network (IN) for connection-oriented communication services in a communication network. For example, a CAMEL platform (customized applications for mobile network enhanced logic) is thus defined according to the GSM Recommendation 03.78 for mobile radio telephone networks according to the GSM standard (global system for mobile communication) in order to enable a worldwide use of the performance features of the intelligent network. The standard architecture of the intelligent network provides a service switching function and a service control function that are connected to one another via a signaling link. A specific protocol that is composed of the CAP protocol (CAMEL application part) for the mobile radio telephone network is thereby employed as application.
New data services such as the packet data service GPRS (general packet radio service) according to GSM Recommendation 03.60 are being currently introduced in existing mobile radio telephone networks according to the GSM standard. The transmission in the mobile radio telephone network thereby does not occur connection-oriented but in the form of packet data. This type of transmission utilizes the given transmission resources in the mobile radio telephone network better. The architecture for the packet data service assumes that the communication terminal equipment used by the mobile subscriberxe2x80x94the mobile stationxe2x80x94is services at its respective location by a service network node (serving GPRS support node). Access to a packet data network is necessary in order to receive or send packet data. To this end, access network nodes (gateway GPRS support nodes) are offered that respectively realize the access to the packet data networkxe2x80x94for example, Internetxe2x80x94and support a specific packet data protocolxe2x80x94for example, Internet protocol. A tunnel via which the packets are transmitted is provided in the mobile radio telephone network between the service network node and the access network node. Since the mobile subscribers with their communication terminal equipment move between a plurality of radio coverage areas of a mobile radio telephone network, the individual subscriber may possibly proceed into the coverage area of a new service network node, so that the tunnel must be switched and the packets are to be transmitted on a new transmission path through the mobile radio telephone network. The previous service network node can no longer control the packet data service for the appertaining subscriber in this case.
It is an object of the present invention to provide a method and a mobile radio telephone network with which the use of the packet data surface can continue to be enabled for the mobile subscriber given a change of the coverage area.
Proceeding from the handling of a packet data service in the mobile radio telephone network by service network nodes in conjunction with an access network node for the transmission of packet data as well as a tunnel switching given a change of the coverage area, the following ensues. An interworking of the packet data service with network functions of an intelligent network whereof a service switching function is interconnected with the respective service network node and a service control function is connected via an interface to the service network node with integrated service switching function. Given the change of the mobile subscriber from the one coverage area into the other coverage area, a switching from an old association that exists between the service switching function integrated in the previous service network node and the service control function to a new association that exists between the service switching function integrated in the new service network node and the service control function ensues in addition to the switching from the one tunnel to the other tunnel. Only by combining integration of the service switching function into the respective service network node, communication with the service control function, and switching from old association to new association in addition to the switching of the tunnel for the packet data transmission, can packet data service be advantageously handled and controlled like other IN services and also continue to be available to the mobile subscriber (unnoticed and disturbance free) by application of IN functions given a change of the coverage area. The interface between the respective service network node with integrated service switching function and the service control function supports a uniform service handling even given a change of the coverage area, whereby the switching of the association is accompanied by the tunnel switching for the exchange of data, messages and signaling information.
According to a development of the invention, status data that are employed for switching the association between service switching function and service control function are reported from the previous service network node to the service control function before the end of the tunnel switching. The advantage of this modification lies therein that an association that already exists between the service switching function in the previous service network node and the service control function with respect to the subscriber who changes is utilized for reporting the association switching.
According to an alternative development of the invention, status data that are employed for switching the association between service switching function and service control function are requested by the service control function and are reported from the previous service network node. A direct communication between the service switching function the new service network node and the service control function results for information about the new responsibility for the packet data transmission.
According to another alternative development of the invention, status data that are employed for switching the association between service switching function and service control function are reported directly between the old service network node with integrated service switching function and the new service network node with integrated service switching function. In this version, a direct handover of the status data with respect to the association can already advantageously ensue during the interrogation of the new service network node, so that the new service network node is responsible from this moment on for monitoring the packet data stream and, due to the new association, can already supply the current data given log on at the service control function.
According to other beneficial versions of the invention, the new service network node with integrated service switching function reports at the service control function before or after the tunnel switching, continues the monitoring of the packet data transmission on the basis of the new association and makes the status data available to the service control function.
An advantageous development of the invention provides that the service control function receives data with reference whereto it recognizes that a switching of the association is involved and it can assume the monitoring of the packet data transmission.